Polymer-based nanocomposite materials and methods of production thereof

ABSTRACT

Polymeric-based nanocomposites with different structures using core-shell particles. The present invention provides a method for producing polymer-based core-shell nanocomposite structures. The nanocomposite materials may be produced with voids in them which may be partially or completely filled with other materials. The core and shell materials may be formed from multicomponent materials, in the case of the coresthese may be for example multiple oxides, semiconductors and in the case of the polymer shell material multiple polymers in blends or copolymers.

FIELD OF THE INVENTION

[0001] The present invention relates to polymer based nanocompositematerials and their methods of production.

BACKGROUND OF THE INVENTION

[0002] In the recent decade, polymer-based nanocomposite materials haveattracted a great deal of attention because of their applications invarious high-tech applications, such as micromechanical devices, memorystorage media, chemical and biochemical sensors, display devices, andphotonic band-gap materials. Generally, colloid crystals are employedeither as templates for producing ordered 2D or 3D structures, (Holland,B T, Blanford, C F, Stein A. Science 1998, 281, 538; Zahidov, A. A. etal. Science 1998, 282, 897; Wijnhoven, J. E. G., Vos, W. L. Science1998, 281, 802; Lenzmann, F., Li, K., Kitai, A. H., Stöver Chem. Mater.1994, 6, 156) for example, in the fabrication of photonic bang gapmaterials or on their own right as chemical sensors (Holtz, J. H.,Asher, S. A. Nature 1997, 389, 829) and devices for memory storage(Kumacheva, E.; O. Kalinina; Lilge, L. Adv. Mat. 1999, 11, 231).

[0003] Recently, a new approach to producing 3D polymer-basednanocomposites has been proposed. This method employs latex particlescomposed of hard cores and somewhat softer shells (Kalinina, O.;Kumacheva. E. Macromolecules 1999, 32, 4122). U.S. Pat. No. 5,952,131 toKumacheva et al., the contents of which are incorporated herein byreference, discloses a material having a matrix composed of particleshaving a core resin and a shell resin. FIG. 1a demonstrates the stagesin fabrication of such a nanocomposite material from core-shell latexparticles. Core-shell latex particles, composed of hard cores andsomewhat softer shells, are synthesized at step A. The particles arepacked in a close packed array, at step B, and annealed at step C at thetemperature that is above the glass transition temperature, T_(g), ofthe shell-forming polymer (SFP) and below the T_(g) of the core-formingpolymer (CFP). As a result, the latex shells flow and form a matrix,whereas the rigid cores form a disperse phase.

[0004] With this approach, it is known to incorporate functionalcomponents into the CFP. When the diffusion of the functional componentbetween the cores and the shells is sufficiently suppressed,nanocomposite materials with a periodic modulation in composition areproduced. It is also known to prepare materials with a direct structurein which fluorescent core particles are embedded into an optically inertmatrix.

[0005] It would be very advantageous to be able to produce ananocomposite template array that would enable one to incorporate a widearray of materials, either organic or inorganic based materials into thetemplate and to facilitate a method of rapidly and economicallyproducing a broad range of polymer-based nanocomposites with periodicmodulations in composition and properties. Such materials would haveapplications in memory storage, photonic crystals, micromechanicalactuators, devices for telecommunications, interference andhigh-refractive index coatings, bio- and chemical sensors.

SUMMARY OF THE INVENTION

[0006] The present invention provides a method for producingpolymer-based core-shell nanocomposite structures with numerouscombinations of properties of the constituent particles and the matrix.

[0007] The present invention provides polymer-based nanocompositesobtained by synthesizing core-shell particles with organic or inorganiccores and polymeric shells; arranging them in one-, two-, orthree-dimensional arrays, and annealing them at the temperature at whichpolymeric shells flow.

[0008] The present invention provides a nanocomposite material,comprising;

[0009] a plurality of rigid core particles embedded in a polymericmaterial and including air voids located in said polymeric material.

[0010] The rigid core particles and the soft polymeric shells may have asingle-component or a multicomponent structure providing a route tomulticomponent nanocomposite materials.

[0011] The present invention also provides a nanocomposite material,comprising;

[0012] a plurality of rigid core particles embedded in a polymericmaterial, said rigid core particles comprising multicomponent organic orinorganic materials.

[0013] The present invention also demonstrates that the ratio betweenthe dimensions of the particle cores and shells can be manipulated toproduce a material containing voids that may be filled with variousspecies.

[0014] In another aspect of the present invention there is provided amethod of synthesizing a nanocomposite material, comprising;

[0015] coating a plurality of rigid substantially spherical coreparticles with a polymeric shell material, said core particles having aradius r_(c) and said polymeric shell material coating said coreparticles having a thickness I_(s), selecting the radius r_(c) of therigid spherical core particles and the shell thickness I_(s) to satisfy0.05<I_(s)r_(c)<0.2, said polymeric material having a glass transitiontemperature above room temperature, the rigid core particles havingsoftening temperature greater than a softening temperature of saidpolymeric material such that upon annealing the polymeric materialsoftens and flows while the rigid core remains solid;

[0016] producing one of a one-dimensional, two-dimensional andthree-dimensional array with the coated rigid core particles; and

[0017] heating said array above the softening temperature of thepolymeric material at which it flows to form a continuous phase havingair voids dispersed therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The method of producing polymer-based core-shell nanocompositestructures according to the present invention, will now be described, byway of example only, reference being had to the accompanying drawings,in which:

[0019]FIG. 1a is a diagrammatic representation of a Prior Art method offormation of polymer-based nanocomposite material, stage A: synthesis ofthe core-shell particles with hard cores and soft shells, stage B:assembly of particles in a 1D, 2D, or 3D close-packed structure, stageC: heat treatment of the particle compact that leads to flow of softshells and formation of a nanocomposite polymer;

[0020]FIG. 1b is a diagrammatic representation of a portion of steps Band C of FIG. 1a the prior art method of formation of polymer-basednanocomposite material using a thick polymeric shell that ensures acontinuous void-free core-shell composite material;

[0021]FIG. 2 shows the principle of the preparation of a nanocompositematerial containing voids in accordance with the present invention;

[0022]FIG. 3 shows a laser confocal fluorescent microscopy image of thenanocomposite material containing voids, the scale bar is 2 μm, the sizeof the fluorescent poly (methyl methacrylate) core particles is 0.5 μm,the thickness of the poly (methyl methacrylate)-poly (butylmethacrylate) shells is 0.08 μm;

[0023]FIG. 4 is an Atomic Force Microscopy image of the nanocompositematerial formed from the core-shell particles with conductive polypyrrolcores and poly (butyl acrylate) shells;

[0024]FIG. 5 shows polypyrole cores covered with poly (butylmethacrylate) (PBMA) particles;

[0025]FIG. 6 shows core-shell polypyrrole-poly (butyl methacrylate)particle size as a function of the ratio between the weightconcentration of the core- and shell-forming particles;

[0026]FIG. 7 shows the polydispersity of the core-shell polypyrrole-poly(butyl methacrylate) particles as a function of the ratio between theweight concentration of the core- and shell-forming particles:

[0027]FIG. 8 is an Atomic Force Microscopy image of the nanocompositematerial formed from the core-shell particles containing silica coresand poly (methyl methacrylate) shells, the size of silica particles is0.6 μm;

[0028]FIG. 9 is a diagrammatic representation of a method of producingmultilayer cores by using silica particles as templates and attachingtitanyl sulfate or titanium oxide coating to the core particles;

[0029]FIG. 10 shows the mass ratio TiO₂/SiO₂ in the core shell particlesas a function of ratio TiOSO₄/surface area of SiO₂, squares are thecalculated ratio, diamonds are the experimental results obtained byelemental analysis;

[0030]FIG. 11 shows the structure of SiO₂ particles as a function of theweight concentration of titanyl sulfate in dispersion;

[0031]FIG. 12 is a Scanning Electron Microscopy image of the silicaparticles (a) and silica particles coated with TiO₂ shells (b), the sizeof silica particles is 580 nm, the diameter of the SiO₂—TiO₂ particlesis 0.78 μm;

[0032]FIG. 13 is an Atomic Force Microscopy image of the nanocompositematerial formed from the core-shell particles with SiO₂—TiO₂ cores andpoly (methyl methacrylate) shells; and

[0033]FIG. 14 shows Bragg diffraction patterns of the films formed fromthe core-shell particles with SiO₂—TiO₂ cores and poly (methylmethacrylate) shells.

DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention describes a process for producingpolymer-based core-shell nanocomposite structures. Particularly, theinvention provides core-shell nanocomposite structures having periodicvoids dispersed throughout the structure. The invention also providescore-shell nanocomposite structures in which the cores comprisemulti-component constituents in which the differing constituents maycover the ambit of both organic and inorganic materials and thesestructures are produced both with and without periodic voids dispersedthroughout the material.

[0035] The schematics of the approach for growing a polymer-basednanocomposite with a continuous core-shell structure is shown in FIG 1a. As discussed in the introduction, stage A involves the synthesis ofthe core-shell latex particles that consist of a hard core and asomewhat softer shell. The materials chosen for the synthesis of thecore and shell materials must satisfy two important requirements. First,the temperature of softening of the core-forming material (CFM) and theshell-forming polymer (SFM) should be such that upon annealing the SFMsoftens and flows while the CFM remains intact. Second, theshell-forming material must have the glass transition temperature wellabove the room temperature. Any possible diffusion of species betweenthe core and the shell during synthesis or during annealing should besuppressed to give a distinct or abrupt well defined boundary betweenthe core and shell.

[0036] Several non-limiting and purely exemplary examples are givenbelow to demonstrate different combinations of materials incorporatedinto the core- or shell-forming polymers.

EXAMPLE 1

[0037] Formation of the Nanocomposite Material with Voids Available forFurther Incorporation of Functional Species

[0038] The principle of tuning of the structure of the nanocompositematerial to incorporate periodic voids is shown in FIG. 2. The ratiosbetween the volume fractions of the CFM and the SFM leading to formationof the nanocomposite material with voids is shown in Table 1 in ashadowed area while the fractions outside of the shadowed section of theTable give a continuous structure. To form a homogeneous matrix theratio between the thickness of the shell, I_(s), and the radius of thecore (r_(c)) should exceed 0.2, i.e., I_(s)/r_(c)<0.2. When0.05<I_(s)/r_(c)<0.2, the amount of the CFM is not sufficient to form acontinuous matrix and small voids are left between particles. The recipeof one embodiment of a synthesis of the core-shell particles withfluorescent polymeric cores and optically inert polymeric shells leadingto this type of structure is given in Table 2. It is evident from FIG. 2that the composite structure comprises voids 22 periodically dispersedthroughout the material. FIG. 3 shows a laser confocal fluorescentmicroscopy image of a nanocomposite material containing voids in whichboth the core and shell are polymer materials. Fluorescent cores appearas bright domains, whereas black domains correspond to air voidsavailable for filing them with different polymer or inorganic materialsusing electrochemical approaches, vacuum deposition, or capillaryinfiltration with liquid phases. The size of the fluorescent poly(methyl methacrylate) core particles is 0.5 μm, the thickness of thepoly (methyl methacrylate)-poly (butyl methacrylate) shells is 0.08 μm.The scale bar is 2 μm.

[0039] The cores may be formed of organic. e.g. polymeric materials orinorganic materials including oxides such as TiO₂, SiO₂ and the like. Atthe assembly state analogous to stage B in FIG. 1a (but with theappropriate core-shell ratios to give periodic voids) the core-shellparticles are arranged in a one-dimensional, two-dimensional, orthree-dimensional array by using sedimentation, electrodeposition orcentrifugation. Fabrication of the composite material is completed byannealing of the dry compact (analogous to stage C in FIG. 1a). At thisstage, the composite material is heated above the softening point of theSFM, at which it flows and fills partly or completely voids between thecore particles and forms a continuous phase. In this approach, the SFMshould be such that the shells possess enough elasticity to act as abarrier to prevent the aggregation of the cores.

[0040] The present method disclosed herein provides several levels ofcontrol of the structure and function of the nanocomposite. First, thediameters of the cores and the thicknesses of the shells may be variedand controlled leading to the variation in particle size and numberdensity in the nanocomposite material. Secondly, the shape of thecore-shell particles i.e. spherical shape versus a rod-like shape, canbe manipulated at stage A. Third, the suggested approach providesseveral types of morphologies of the ultimate composite material. Whenthe shells are sufficiently thick, the SFM fills gaps between the coreparticles, i.e., forms a continuous matrix. For thin shells, the rigidparticles are just “glued” together by the SFM. In this way compositematerials are formed, in which small voids between particles can befilled with another functional material. Finally, the composition of theCFM and the SFM can be varied and controlled in a variety of ways,several of which will be described below.

[0041] The core-shell particles can be monodispersed or polydisperseddepending on a desired application of the nanocomposite material. Toform nanocomposites with ordered structures, the core particlespreferably are monodisperse, the shells are preferably uniform inthickness, and the entire core-shell particles are monodispersed. TheCFM may be either a single or multicomponent material. In themulticomponent cores, several species can form distinct layers or can bemixed to form a homogeneous phase. The multicomponent materials may beinorganic based materials e.g. oxides, or multicomponent organicmaterials, e.g. polymer mixtures, blends and the like.

[0042] The structure of the nanostructured material with necks betweenmonodispersed colloid particles and voids between the particles issimilar to the structure of templates used for producing photonic bandgap materials, (REF) but has a much better processibility (e.g. it canbe polished) and resistance to cracking. Due to the presence of voidsand ordered structure the material appears as highly irridiscent, andcan be used as diffraction coating or free-standing film. Alternatively,the voids may be filled with photosensitive materials such as dyes orchromophores. For example, a monomer covalently labeled or mixed with afluorescent dye with the absorption peak similar or different then theabsorption peaks of the dye(s) incorporated in the core and/orcore-forming polymer may be used for several applications including datastorage media. Under imaging of the structure different materialmorphologies will be observed for different wavelengths of irradiation.Local photobleaching of a particular dye in the specific lateral orvertical plane will enable one to incorporate a secret code in thincoating for security needs.

[0043] Alternatively, inorganic, e.g. semiconductor particles may beincorporated into the voids using capillary flow, infiltration or vacuumdeposition. First, upon dissolution of the particles, octahedralnanostructures will be obtained which have a very high control overtheir dimensions and monodispersity. Second infiltration of a monomer ora polymer mixed with inorganic material, having nonlinear propertieswill lead to the periodic modulation of optical properties of thematerial.

EXAMPLE 2

[0044] Polymer-based Nanocomposite Material Formed from Core-shellParticles with Electroconductive Polymer and Dielectric Shells

[0045] Conductive monodisperse polypyrrole particles with the dimensionsvarying 0.08 to 300 μm covered with the dielectric poly (butylacryalate) shells were synthesized using the recipe given in Table 3. Afilm formed from polypyrrol particles showed a finite conductivity. Whenan elastomeric layer comprised of a cross-linked poly (butyl acrylate)was attached to the core particles, a film formed by annealing of thesediment formed by the core-shell particles showed conductivitydepending on the thickness of the elastomeric shells. Very smallstretching of the film led to significant drop in conductivity. Thesefilms can be used for non-destructive control of strains in variousmaterials or be incorporated in micromechanical devices in whichthorough control of small displacements is required. FIG. 4 is an AtomicForce Microscopy image of the nanocomposite material formed from thecore-shell particles with conductive polypyrrol cores and poly (butylacrylate) shells.

[0046] The polymeric CFM can be represented by a pure polymer or apolymer which is functionalized by either chemically attached functionalgroups or mixing it with appropriate low or high-molecular weightspecies. When the core-shell particles are made from dissimilarmaterials and the affinity between the core and the shell material isnot sufficient to provide adhesion between the cores and the shells,interfacial polymerization is not efficient and the shell-formingpolymer was found to nucleate and polymerize in the bulk rather that onthe surface of the core particles. In this situation, the attachment ofshells was provided by electrostatic attraction between cores andshell-forming particles synthesized from materials carrying oppositecharges, as is shown in FIG. 5. After attachment the shell-formingpolymer was annealed to form a dense and uniform shell, which could belater transformed into a matrix.

[0047] The amount of the shell-forming polymer to the core-formingpolymer had to provide a dense coverage of the core particles with atleast a monolayer of the shell-forming particles. As is shown in FIGS. 6and 7, only under these conditions core-shell particles with thewell-defined size and high monodispersity could be produced aftercoating the core particles.

EXAMPLE 3

[0048] Polymer Nanocomposites Formed by Inorganic Particles Embedded ina Polymeric Matrix

[0049] Monodispersed silica particles were synthesized using a recipeshown in Table 4. Poly (methyl methacrylate) shell was attached to thesilica particles, and a sediment of the core-shell particles was heatedat the temperature leading to flow of PMMA. FIG. 8 shows an Atomic ForceMicroscopy image of the nanocomposite material formed from thecore-shell particles containing silica cores and poly (methylmethacrylate) shells. The size of silica particles is 0.6 μm.

EXAMPLE 4

[0050] Polymer Nanocomposites Formed by Multicomponent InorganicParticles Embedded in a Polymeric Matrix

[0051] Multilayer cores could be produced by using silica particles astemplates and attaching titanyl sulfate or titanium oxide coating to thecore particles, as is shown in FIG. 9. Monodispersed silica particleswere synthesized using a recipe shown in Table 4. A titanium oxide layerwas synthesized on the top of silica particles using a recipe shown inTable 5. In general, the volume of TiO₂ varied from 0.05 to 0.4 withrespect to the volume of the silica particles. Referring to FIG. 10, avery important requirement in the preparation of monodispersed bilayerinorganic cores is the exact ratio between the surface area of silicaparticles and the amount of titanyl sulfate added to silica dispersion.FIG. 10 shows the mass ratio TiO₂/SiO₂ in the core shell particles as afunction of ratio TiOSO₄/surface area of SiO₂. Squares: calculatedratio; diamonds. The experimental results were obtained by elementalanalysis. The surface area of silica particles in the system wascontrolled by either silica particle size, or by their concentration inthe dispersion. Referring to FIG. 11 shows the structure of the silicaparticles (FIG. 11a) and coated silica particles when titanyl sulfate isdeficient (FIG. 11b), in optimum ratio (FIGS. 11c and d), and in excess,(FIG. 11f). FIG. 12 is a Scanning Electron Microscopy image of thesilica particles (a) and silica particles coated with TiO₂ shells (b).The size of silica particles is 580 nm, the diameter of the SiO₂—TiO₂particles is 0.78 μm. FIG. 13 shows an Atomic Force Microscopy image ofthe nanocomposite material formed from the core-shell particles withSiO₂—TiO₂ cores and poly (methyl methacrylate) shells. Films formed inthis manner, showed strong Bragg diffraction patterns, specifically,FIG. 8 shows Bragg diffraction patterns of the films formed from thecore-shell particles with SiO₂—TiO₂ cores and poly (methyl methacrylate)shells.

[0052] In such films, the position of the diffraction peak strictlydepends on the dimensions of the cores and shells, therefore such filmscan be used as interference high-refractive index polymer-based coatingsfor, e.g security paper. Alternatively, the inorganic particles can beobtained from semiconductors e.g. CdS—CdSe and then coated with apolymeric shell. Upon annealing the quantum dots will be incorporated inthe polymeric matrix (quantum dots). Materials exhibitingelectroactivity may be incorporated into the voids.

[0053] The multicomponent materials of which the cores and/or shells areproduced may comprise two or more different materials. For example thecores may be made of two or more several different oxide materials, inlayers or a homogenous mixed oxide. The same applies to the polymericshell materials, the multicomponent shells may be made of two or morepolymers in blends, block copolymers and the like.

[0054] The foregoing description of the preferred embodiments of theinvention has been presented to illustrate the principles of theinvention and not to limit the invention to the particular embodimentillustrated. It is intended that the scope of the invention be definedby all of the embodiments encompassed within the following claims andtheir equivalents. TABLE 1 Volume Fraction of the CFP in the PolymerNanocomposite Formed from Core-Shell Particles with the Different CoreDiameter and Shell Thickness. L_(s) = r_(p) − R_(c), μm r_(c), μm 0.150.20 0.25 0.30 0.35 0.40 0.45 0.50 0.60 0.025 42 52 58 63 67 70 73 75 790.050 22 30 36 42 47 51 55 58 63 0.075 12 19 24 30 34 38 42 46 51 0.1008 12 17 22 26 30 33 36 42 0.125 5 9 12 16 20 23 26 30 35 0.150 4 6 9 1316 19 22 24 30 0.175 3 5 7 10 12 15 18 20 25 0.20 2 4 6 8 10 12 15 17 220.25 1 2 4 5 7 9 10 11 18

[0055] TABLE 2 Recipe for the Three-Stage Emulsion Polymerization of the1050 nm Core-Shell Latex Particles Stage 1 Stage 2 Stage 3 Precharge:Deionized water, g 70 70 40 Seeds from previous step, g — 20 20Potassium persulfate, g 0.2 — — AIBN, g — 0.005 0.005 Pumping mixture:MMA, g 30 7 2 BMA, g — — 1 DDM, g 0.088 0.052 0.136 EGDMA, g 1.068 0.032— NBD-MMA, g 0.01 0.0035 — AIBN, g — 0.052 0.186 Ionic initiatorsolution added simul- taneously with the monomer mixture: Potassiumpersulfate, g — — 0.0026 Water, g — — 2.6 Particle size, nm 500 640 745

[0056] TABLE 3 Recipe for the synthesis of the core-shell particles withconductive cores and dielectric shells Pyrrole, FeCl₃ Stabilizer* H₂Obutyl acrylate DDM K₂S₂O₄ Ml g g ml ml g g 0.3-1.0 5.47 0.3-1.0 100 20.13 0.1

[0057] TABLE 4 Recipe for the synthesis of the SiO₂ Tetraethyl TotalOrthosilicate, % volume, Reaction Particle ml Ethanol H₂O % NH₃ ml Timesize 20 234 14.4 0.84 300 3 hr 580 nm 20 234 13.8 1.4 300 1 hr 340 nm 20234 10.25 0.63 285 6 hr 120 nm

[0058] TABLE 5 Recipe for the synthesis of the SiO₂—TiO₂ particlesSilica particles, Volume 0.2 M Total with the diameter, Silica solidTiOSO₄ in reaction, Particle nm content, % 1M H₂SO₄ ml volume, ml sizenm 220 30 25 225 260 220 0.8 100 400 1000 580 1.0 40 440 780

Therefore what is claimed is:
 1. A nanocomposite material, comprising; aplurality of rigid core particles embedded in a polymeric material andincluding a plurality of voids located therein.
 2. The nanocompositematerial according to claim 1 wherein said core particles and said airvoids are periodically disposed throughout said polymeric material. 3.The nanocomposite material according to claims 1 or 2 wherein said rigidcore particles are substantially spherical particles.
 4. Thenanocomposite material according to claims 1, 2 or 3 wherein said rigidcore particles comprise multicomponent organic or inorganic materials orsingle-component materials.
 5. The nanocomposite material according toclaims 1, 2, 3 or 4 wherein said polymeric material comprisesmulticomponent or single-component polymers.
 6. The nanocompositematerial according to claims 1, 2, 3, 4 or 5 wherein said voids arepartially or completely filled with a functional material.
 7. Thenanocomposite material according to claim 6 wherein the functionalmaterial is selected from the group consisting of conducting materials,semiconductors, dielectrics, magnetic materials, polymeric materials,optically-sensitive materials and liquid crystal materials.
 8. Thenanocomposite material according to claims 1, 2, 3, 4, 5, 6 or 7 whereinsaid rigid core particles include an electroconductive polymer andwherein said polymeric material includes a dielectric polymer.
 9. Thenanocomposite material according to claim 8 wherein saidelectroconductive polymer comprises electroconductive polypyrrole, andwherein said dielectric polymer comprises cross-linked poly (butylmethacrylate).
 10. The nanocomposite material according to claim 8wherein said rigid core particles comprise multicomponent inorganicoxide spheres.
 11. The nanocomposite material according to claims 1, 2,3, 4 or 5 wherein said rigid core particles comprise multicomponentoxide spheres.
 12. The nanocomposite material according to claim 11wherein said multicomponent oxide spheres each include a silica spherecoated with another oxide shell.
 13. The nanocomposite materialaccording to claim 12 wherein said other oxide forming said oxide shellis TiO₂.
 14. The nanocomposite material according to claims 11, 12 or 13wherein said polymer material is poly (methyl methacrylate).
 15. Thenanocomposite material according to claim 7 wherein saidoptically-sensitive material is a fluorescent dye or chromophore thatfluoresces at a first wavelength, including a second fluorescent dye orchromophore that fluoresces at a second wavelength incorporated intosaid polymeric shell material, and including a third fluorescent dye orchromophore that fluoresces at a third wavelength incorporated into, orbound to, said core particles.
 16. The nanocomposite material accordingto claim 4 wherein said multicomponent core includes at two differentcomponents.
 17. The nanocomposite material according to claim 4 whereinsaid multicomponent core includes at three or more different components.18. A nanocomposite material, comprising; a plurality of rigid coreparticles embedded in a polymeric material, said rigid core particlescomprising multicomponent organic or inorganic materials.
 19. Thenanocomposite material according to claim 18 which is periodic.
 20. Thenanocomposite material according to claims 18 or 19 wherein said rigidcore particles comprise multicomponent organic materials ormulticomponent inorganic materials, or a combination of organic andinorganic materials.
 21. The nanocomposite material according to claims19 or 20 wherein said polymeric material comprises multicomponent orsingle-component polymers.
 22. The nanocomposite material according toclaims 19, 20 or 21 including a plurality of air voids dispersedtherethrough.
 23. The nanocomposite material according to claim 22wherein said voids are partially or completely filled with a functionalmaterial.
 24. The nanocomposite material according to claim 21 whereinthe functional material is selected from the group consisting ofconducting materials, semiconductors, dielectrics, magnetic materials,polymeric materials, optically-sensitive materials and liquid crystalmaterials.
 25. A method of synthesizing a nanocomposite material havingair voids, comprising; coating a plurality of rigid substantiallyspherical core particles with a polymeric shell material, said coreparticles having a radius r_(c) and said polymeric shell materialcoating said core particles having a thickness I_(s), selecting theradius r_(c) of the rigid spherical core particles and the shellthickness I_(s) to satisfy 0.05<I_(si)r_(c)<0.2, said polymeric materialhaving a glass transition temperature above room temperature, the rigidcore particles having softening temperature greater than a softeningtemperature of said polymeric material such that upon annealing thepolymeric material softens and flows while the rigid core remains solid;producing one of a one-dimensional, two-dimensional andthree-dimensional array with the coated rigid core particles; andheating said array above the softening temperature of the polymericmaterial at which it flows to form a continuous phase having air voidsdispersed therethrough.
 26. The method according to claim 25 whereinsaid array is grown using sedimentation, electrodeposition,centrifugation, or water filtration.
 27. The nanocomposite materialaccording to claims 25 or 26 wherein said rigid core comprisesmulticomponent organic or inorganic materials or single-componentmaterials.
 28. The nanocomposite material according to claims 24, 25 or26 wherein said polymeric shell comprises multicomponent orsingle-component polymers.
 29. The method according to claims 25, 26, 27or 28 wherein a functional material is infiltrated into said voids. 30.The method according to claim 29 wherein said functional materials isinfiltrated into said voids by one of capillary infiltration, diffusion,electrochemical deposition and vacuum vapor deposition.
 31. Thenanocomposite material according to claim 1 wherein said rigid coreparticles have an aspect ratio greater than unity.